alistairfontaine/purity-fs

Purity-FS is a virtual filesystem written entirely in pure C++20, meaning it stores files and folders inside a single container file on your real disk instead of relying on the operating system's own filesystem. It uses only the C++ standard library, with no outside dependencies, so there is nothing to break when a third party library changes or gets removed. Inside that container, Purity-FS keeps track of files using a linked chain of fixed size blocks, similar to how a real disk allocates space in sectors. A block allocation table held in memory keeps note of which blocks belong to which file, and large files get split across many blocks as needed. Before writing file data to disk, the tool scrambles the bytes using a simple XOR bit mask, a lightweight technique that changes the bytes in a reversible way but is not a strong encryption method. The project also includes a small command line shell for working with the filesystem directly. From this shell you can format a new virtual disk file, mount an existing one, create and move between directories, list contents, and write or read files. Two more commands let you import a real file from your computer into the virtual filesystem, or export a file back out to your local disk. The README describes this as version 1.0.0, a stable release, and presents it as an educational and self contained project rather than a production storage system, since it relies on a simple XOR mask rather than genuine cryptographic protection. It is released under the MIT license, so anyone can use, modify, or distribute it freely.